1. Field of the Invention
This invention relates to diamond drag bits for drilling earthen formations having polycrystalline diamond inserts imbedded in the cutting face of the bit.
More particularly, this invention relates to matrix type diamond drag bits fabricated by a powder metallurgy process wherein cutter pockets and relief pockets are formed in a female mold to accept and support cylindrically shaped polycrystalline diamond inserts subsequently brazed in place in the pre-formed pockets.
2. Description of the Prior Art
Typically, milled relief pockets adjacent cutter pockets formed in matrix bits are vectored parallel with the cutter pockets resulting in inadequate support for the cylindrical shaped PCD cutters.
The present invention provides a milled relief pocket adjacent the cutter pocket that is vectored at a different angle than the angle of the cutters oriented in the face of the matrix bit. The relief pocket provides maximum compression support for the base of the PCD cylindrical and increased cylindrical wall support while relieving the cutter backrack surface.